This study explored the mathematical beliefs of two second-grade teachers. This exploration included 1) the nature of mathematics beliefs and orientation towards teaching and learning held by the teachers, 2) how their beliefs were developed and, when applicable, changed, and 3) how their beliefs influenced their mathematics instruction. It used the work of Green (1971) as its theoretical framework, Ernest (1989) for identification of nature of mathematics beliefs, and Askew et al., (1997) for identification of the orientations towards teaching and learning. This study found that the teachers tended to hold instrumentalist beliefs and transmissive to discovery orientations. It also supported the notion that the teachers' initial beliefs appeared to be developed by their experiences as a K-12 learner and curriculum use and experiences with students tended to be the catalyst for changes in their beliefs. Finally, this study found that the teachers' espoused and enacted beliefs tended to align more than contradict and any contradictions could be because of other factors such as beliefs about their students' abilities or misunderstandings about how to incorporate productive teaching and learning practices (NCTM, 2014). The purpose and results of this study could provide valuable insight on ways to create and implement effective professional development sessions. Additionally, this study suggested that further research should be conducted to determine if the more effective professional development sessions would be sufficient enough to cause changes in in-service teachers or if it needed to be replaced or supplemented with math coaches that work within and with the teachers in the classroom. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]